The proposed study aims to explore the effects of classroom sound field amplification on phonological awareness, concept comprehension, and teacher ratings of educational risk among first grade children with and without middle ear pathology (measured by repeated tympanometric and pure-tone screening procedures using ASHA, 1990, guidelines). The primary hypothesis is that first grade children in experimental (amplified) classrooms with evidence of middle ear pathology will show pre-/post-test performance increments on measures of phonological awareness, concept comprehension, and classroom success that exceed those of peers with middle ear pathology in control (nonamplified) classrooms. The study will be conducted using a 2-factor repeated measures design with 3 dependent measures. The two independent variables will be: (1) presence or absence of classroom amplification, and (2) presence or absence of middle ear pathology. The three dependent variables will be scores on: (1) a 21-item phonological deletion task designed by Catts, Swank, McIntosh, and Stewart), (2) the Boehm Test of Basic Concepts -- Revised, and (3) the Screening Instrument for Targeting Educational Risk. Subjects will be approximately 480 children in 18 classrooms (9 amplified experimental classrooms and 9 control classrooms) from four school districts (see letters of commitment). Teachers who use sound field amplification systems will receive inservice training from the staff of Project MARRS (see letter of agreement). All teachers will be volunteers. Dependent measures will be used as pre- and post-tests in September and May of the first grade year for two consecutive classes of children. It is anticipated that children from four classrooms can be tested in one day, using multiple stations and trained, supervised graduate students in speech-language pathology and audiology. Evidence of middle ear pathology will be based on a standard tympanometric and audiometric screening protocol. Children will be assigned to either high-risk or low-risk middle ear pathology groups based on the frequency with which they fail tympanometric screenings, performed at least 4 times for all Ss (September, November, January, March). Children who fail any of the four screenings but do not meet the criteria for immediate medical/audiological referral will be retested (tympanometry, audiometry, or both, in accordance with the ASHA guidelines) within 4-6 weeks of the screening failure. Children who fail no scheduled screening or who fail one scheduled screening but pass the following 4-6 week retest will be in the low-risk group. Children who fail more often will be in the high- risk group. In addition to MANOVA to test the main hypotheses, the data regarding number of tympanometric screening failures (0-8) will be used to perform correlation analyses to determine whether more severe problems are associated with more frequent evidence of middle ear pathology. The project will extend findings from previous informal studies that support classroom amplification as a method to reduce the negative effects of minimal fluctuating hearing loss. It also promises to provide new insights about the relationships among middle ear functioning, phonological awareness, comprehension of relational concepts, and teacher-ratings of classroom success.